The invention relates to a multimode universal mobile telecommunications system, and particularly it relates to a system in which satellite and/or terrestrial mobile communication systems are integrated and in which a subscriber may choose between systems, services and connections on the basis of the price, quality, capacity or other criteria. In this description we will also use shorter names for the different mobile communication systems mentioned above, which will be, respectively, universal multimode system, satellite system and terrestrial system.
All recent studies carried out by various consortia formed for the purpose of providing satellite-based mobile communication services have concluded that a wide area with relatively few service users is a basic criterion for changing into satellite systems. System interworking has also been examined as co-operation between one satellite system and one terrestrial system only, by developing dual-mode terminals which operate only between two systems. In addition, the co-operation of two systems at the dual-mode terminal level is designed such that two subscriber numbers are needed.
The rapid growth of mobile communications especially in business environment and, on the other hand, the need of local users to have access to various satellite and terrestrial systems have set new challenges for the communications field. In the present invention, the key factors in the system interworking are global availability and cost-effectiveness. Therefore, the invention implements universal integration of various satellite-based and terrestrial systems at the radio interface level. Problems concerning the mutual co-operation and interconnections of the various mobile communication systems can be solved at two levels: at the network level and at the mobile terminal level. To modify existing mobile communication networks would be a very expensive solution. On the other hand, many of the problems involved in the integration of different systems can be transferred to the mobile terminal level. In the invention, it is developed a new communication system concept by integrating various satellite and terrestrial systems at the mobile terminal level by making use of a multiple access satellite communication system (MASCS). Such a system provides a transparent subscriber market (TSM) in which several networks may share subscribers, whereby the networks will have more customers without having to fear an overload. This means a significant growth in capacity, which is cost-effective from the point of view of the operators and brings new efficiency in the use of capacity in mobile communications. A universal multimode system eliminates the need to radically change existing mobile communication networks.
The invention may be implemented as an initial step toward rational liberalization of telecommunication services, which may also bring about new standards in the world of communications. From the user""s point of view a multimode system forms a multiple access network (MAN) which includes various satellite-based and terrestrial mobile communication networks and also takes into account the universal mobile telecommunications system (UMTS) and the future public land mobile telecommunication systems (FPLMTS) as possible future entities in the network architecture of the universal multimode system. The advanced solutions, techniques and benefits of the universal multimode system provide the best possible service for the end user and bring rational free competition to the world of telecommunications. Such a system should be implemented before the various satellite systems start to build their networks which indeed are not always economical or user-friendly; nor will their competition with terrestrial mobile communication networks benefit the users or terrestrial mobile communication operators. The universal multimode system realizes the main objectives of global telecommunication; free competition, open accessibility and universal services as well as consideration of local regulations.
The invention relates to a universal multimode mobile communication system which in its embodiment may include:
multimode and dual-mode terminals used by the multimode system to provide the users of these equipment access to two or more satellite-based or terrestrial mobile communication systems,
a selective multiple access system, which includes a price-quality selection system and provides the mobile terminal with information needed to select the optimal network,
price-quality selection procedures for selecting access or handover between or inside two or more satellite or terrestrial networks,
a mobile pricing system including a flexible cell- or network-based pricing system, providing information about service quality and prices for the mobile terminal,
a mobile invoicing system including a smart card management part and a call charging module and a subscriber identity and invoicing module in a mobile terminal and a price information controller and a dynamic accounting system,
a multiple access practice,
a multiple access satellite communication system which provides not only communication services but also methods, services and information listed above, needed in the operation of a dual-mode or multimode terminal, and which also may provide the service prices of all other satellite or terrestrial operators,
a backward relay system to connect and change channels from a cell or beam to another to form virtually fixed cells, and
location registration and call procedures.
It is characteristic of a universal multimode system which connects or links together various terrestrial and satellite-based mobile communication networks that, on one hand, it is an intermediate system between their radio interfaces, ie. an integrated telecommunication protocol, and, on the other hand, that it is a communication system which connects all satellite and terrestrial communication systems to its own multiple access satellite communication system (MASCS). A universal multimode system that provides intelligent methods for dual-mode and multimode mobile terminals creates an entirely new mobility concept. Such terminals include a price-quality function which enables the optimal use of the connections of various mobile communication networks. The price-quality (PQ) selection measures and estimates both the transmission quality and the cost-effectiveness of the service provided by the various networks or just one satellite network and selects on the basis of these parameters the optimal connection (channel) and requests the network to allocate it. The PQ selectivity serves as an access and handover system called PQ-selective access and handover and it gives the mobile terminal full freedom to decide which network""s radio channel to choose. This access and handover method is a new solution giving the mobile terminal access to various networks and eliminating the delay effects of satellite signals. The PQ selection can also be applied to other types of dual-mode or multi-mode mobile stations or fixed terminals. All above-mentioned solutions related to the present invention are new applications of terrestrial and satellite communications and they are very valuable both technologically and commercially.
In order to make mutual co-operation between various mobile communication networks possible, it is imperative to develop solutions for such problems as handover between satellite networks and terrestrial networks and user access to these systems. In addition, a number of smaller problems have to be solved. Handover between a cell in a cellular system and a satellite beam is considered problematic. In the GSM, for example, it is considered problematic because inside a satellite beam there may be two cells with the same broadcast channel (BCCH) and base station identification. In addition, the propagation delay of satellite signals (depending on the positions of different satellites) and the handover from a satellite to the GSM produce overlapping signals, which results in difficulties in the decision-making concerning handover. Therefore, in the universal multimode system, these solutions are integrated in the multimode and dual-mode terminals, which reduces the need for major modifications in the existing systems.
Considering that future cellular mobile networks, integrated into a universal mobile telecommunication system or into a future public land mobile telecommunication system or separate, as today, will be competitors or partners to satellite communication systems, the satellite systems should be able to co-operate with the terrestrial networks so that they can encourage both users and, on the other hand, terrestrial operators to advance integration steadily but effectively. This requires developed solutions for the needs of the users. Since satellite networks have coverage areas covering the terrestrial networks, a dual-mode or multimode terminal should be able to compare both the transmission quality and the price competitiveness of the services provided by these networks. The operation of a dual-mode terminal is restricted between one terrestrial system and one satellite system, but a multimode terminal can access several terrestrial and satellite systems. The PQ selection function provides a mobile terminal with the possibility of using satellite systems or cellular systems on the basis of quality and price competitiveness parameters. Such a terminal will, however, resort to satellite resources if all channels are busy or they operate in areas where there are no terrestrial mobile services available.